Joel's Reading List
Here's Joel Spolskys Recommended Reading List. A great list.
Here are a few books which yours truly would add to a recommended reading list (in descending order of importance):
Refactoring: Improving the Design of Existing Code - Martin Fowler
Extreme Programming Installed - Ron Jeffries et. al.
Test Driven Development: By Example - Kent Beck
Working Effectively with Legacy Code - Michael Feathers
Agile Software Development, Principles, Patterns, and Practices - Robert C. Martin
Extreme Programming Explained - 1st edition - Kent Beck
Code Complete, Second Edition - Steve McConnell
Debugging the Development Process - Steve Maguire
Thinking in C++, Volume 1: Introduction to Standard C++ (2nd Edition) - Bruce Eckel